EXCAVATION AND TRENCHING

To establish procedures for excavation work to help assure excavations are performed in a safe and proper manner.

Definition

Excavations are any man-made cut, cavity, trench or depression in the earth surface formed by earth removal. (OSHA makes no distinction on the depth of excavation.)

Trenches are narrow excavations made below the surface of the ground. In general, the depth is greater than the width. However, the width of a trench is not greater than 15 feet. An excavation is also considered to be a trench

Objective

To comply with OSHA standard 1926.650 "Excavations."

Responsibility

Departmental supervisors must ensure their employees follow these procedures:

1. Prior to Excavation or Trenching

a. Identification of Buried Utilities
All underground utilities (public and University) must be clearly marked to identify potentially hazardous situations prior to starting work requiring excavation. The person responsible for oversight must contact "Call before you dig" (1-800-632-494
9) to identify public utilities. Contact NCSU Physical Plant (515-2181) to identify the location of NCSU utilities.

b. Surface Encumbrances
Remove, support or safeguard all surface encumbrances located at the site that may create a hazard to employees.

c. Competent Person
At each excavation site there must be a designated "competent"
person whenever employees are digging or in the excavation. A
"competent" person means someone capable of identifying existing and
predictable hazards in the surroundings, or working conditions that
unsanitary, hazardous, or dangerous to employees. The
competent person has authorization to take prompt corrective measures
to eliminate any unsafe condition. A "competent" person is someone who
attends a 4 hour excavation/trenching course and successfully passes the
course examination. There must be documentation of the training.

2. Excavation
a. Materials and Equipment
Trench shoring and trench jacks shall be on the site before any
excavation begins when the expected depth will exceed four feet or
where unstable soil is expected. In addition, a radio equipped truck
or portable radio shall be on the site at all times when work is in
progress.

b. Protection of Employees
No one shall enter excavations of four feet or more in depth without
having shoring in place or the banks cut back to a safe angle. (Refer
to OSHA Standard 1926.652) No one shall enter an excavation of less
than four feet without shoring or proper angle of repose unless
authorized by a competent person.

Excavations less than four feet in depth may not require this degree of
protection if examination of the ground by a competent person provides
no indication of a potential cove in. Store excavated material at least
two feet from the excavation edge. Workers must wear hard hats at the
site when work is in progress. Provide a stairway, ladder, ramp or
other safe means of egress in trench excavations that are 4 feet or more
in depth. The travel distance to the ladder must be no more than 25
feet of lateral travel for employees. The ladder must extend three feet
above the edge of the trench.

c. Inspections
A competent person must make daily inspections of excavations, the adjacent areas, and protective systems for evidence of possible cave-ins, indications of protective systems failure, hazardous atmospheres, or other hazardous conditions.
The competent person must conduct an inspection

Prior to the start of work and as needed throughout the shift

After every rainstorm or other hazard increasing occurrence

As dictated by the activity taking place in the trench

When fissures, tension cracks, sloughing, under cutting, water seepage, bulging at the bottom or other similar circumstances occur

When there is any change in the size, location or placement of the soil pile

When there is any indication of change or movement in adjacent structures

Where the competent person finds evidence of a situation that could
result in a possible cave-in, indications of failure of protective
systems, hazardous atmosphere, or other hazardous conditions, remove
exposed employees from the hazardous area until safety measures are in
place.

d. Barricades and Warnings
Take special measures to protect the public because the danger excavation work presents and the high student population on campus. Simple barricades are not enough protection in high traffic areas near sidewalks, and road ways subject to pedestrian
traffic. In high traffic areas, place snow fencing around the excavation to provide maximum protection. An additional precaution is to use barricades with flashing lights whenever possible on pedestrian walkways and roadways.

Provide employees exposed to public vehicular traffic with warning
vests or other suitable garments marked with reflector or
high-visibility material. The supervisor must contact the NCSU Campus Police and apprise them of the excavation and ensure that they check
periodically for vandalism or any other unusual activity.

e. Competent Person Training
To become a competent person, a person needs specialized training. This training is available through Weaver Associates (832-6242). The course will provide information on:

Soil analysis

Use of protective systems

Requirements of 29CFR1926. SUBPART P

Determination of competency requires participant to pass the course final examination. For additional training information contact Scott Mabry, at 515-6871.